The solution growth method has been known as a method for producing a single crystal of silicon carbide (SiC). In the solution growth method, an SiC single crystal is grown on an SiC seed crystal which is in contact with an Si—C solution. The Si—C solution is a solution in which carbon (C) is dissolved into a melt of Si or an Si alloy. It is desirable that carbon is dissolved in the solution as much as possible within a composition range in which the solution and the solid phase SiC are at thermodynamic equilibrium. The SiC seed crystal is brought into contact with the Si—C solution (a liquid phase) such that at least a portion of the solution in the vicinity of the seed crystal is supercooled. This creates a supersaturated condition of SiC in the portion of the solution in the vicinity of the seed crystal, thereby causing an SiC single crystal to grow on the seed crystal.
A general method for creating a supersaturated condition is a so-called temperature difference method. In the temperature difference method, a temperature gradient is provided in the solution such that the temperature of a region in the vicinity of the seed crystal in the solution is lower than the temperature of other portions of the solution.
In the production methods of a single crystal disclosed in JP03-183690A (Patent Literature 1) and JP2006-169073A (Patent Literature 2), a seed crystal is cooled by feeding a gas into a seed shaft with the seed crystal attached. In the production methods disclosed in these literatures, the temperature of a portion in the vicinity of the seed crystal in the solution is made lower than in other portions of the solution by cooling the seed crystal.